The present invention relates generally to a binocular image display apparatus comprising an image display device and a viewing optical system for each of the viewer's both eyes.
So far, there has been a head-mounted image display apparatus known in which small-format image display devices are used to enlarge or magnify original images on those display devices by viewing optical systems for presentation to the viewer. For such a head-mounted image display apparatus, there are overall size and weight reductions demanded because it is mounted on the head for use. To make effects of the images presented more realistic, there is still mounting demand for an optical system capable not only of presenting original images on the display device at as wide an angle of field as possible but also of expressing them with high resolution. For the means for meeting such a demand, proposal has now been made of design for causing images on the left and right image display devices to overlap partly so that the resultant fused image can be stereoscopically viewed.
JP(A) 6-38246 discloses a visual image apparatus comprising a left-eye image display device and a right-eye image display device and eyepiece optical systems for guiding images formed by said image display devices to the left and right eyes of the viewer, respectively, wherein of designs of shifting an image displayed by said left-eye image display device left with respect to an image displayed by said right-eye image display device, and shifting an image displayed by said right-eye image display device right with respect to an image displayed by said left-eye image display device, at least one design is used so that virtual images of images formed by said binocular or left- and right-eye image display devices and projected in midair by said eyepiece optical systems overlap at least partly for stereoscopic viewing of said images.